Blog Archive

Monday, 25 August 2008

Weekly BioNews 18 - 25 Aug 2008

Turning up the heat on the red tomato during processing has the potential to give the popular garden staple added disease-fighting power, Ohio State University research suggests.

Scientists have found that lycopene molecules in tomatoes that are combined with fat and subjected to intense heat during processing are restructured in a way that appears to ease their transport into the bloodstream and tissue. The tomato is the primary food source of lycopene, a naturally occurring pigment linked to the prevention of cancer and other chronic diseases.

In its standard structure in the average red tomato, the lycopene molecule is laid out in a linear configuration. That structure seems to hinder the molecule's absorption through intestinal walls and into the blood, said Steven Schwartz, an investigator in Ohio State's Comprehensive Cancer Center and a professor of food science and technology at Ohio State.

Meanwhile, most of the lycopene that is found circulating in human blood is configured in a bent molecular form. This means that either the human body somehow transforms lycopene molecules through reactions that have yet to be identified, or that the bent molecular structures of lycopene are much more likely to be absorbed into the blood and transported to tissue – a necessary step in preventing disease.

Assuming the latter is true, Schwartz and colleagues have devised a way to process red tomatoes – the variety preferred by American consumers – into a sauce that contains bent molecular forms of lycopene. A clinical trial conducted in collaboration with Steven Clinton, a medical oncologist and physician scientist in Ohio State's Comprehensive Cancer Center, showed that people had more lycopene in their blood after eating the specially processed sauce than they did after eating regular red tomato sauce...

Researchers at the Johns Hopkins Bloomberg School of Public Health's Malaria Research Institute have identified a previously unknown virus that is infectious to Anopheles gambiae—the mosquito primarily responsible for transmitting malaria.

According to the researchers, the discovered virus could one day be used to pass on new genetic information to An. gambiae mosquitoes as part of a strategy to control malaria, which kills over one million people worldwide each year.

The virus, AgDNV, is a densonucleosis virus or "densovirus," which are common to mosquitoes and other insects, but do not infect vertebrate animals such as humans. Although the virus does not appear to harm the mosquitoes, the researchers determined it is highly infectious to mosquito larvae and is easily passed on to the adults.

According to Jason Rasgon, PhD, senior author of the study, the discovery came about serendipitously while the research team was conducting experiments to determine whether Wolbachia bacteria could be used to infect An. gambiae mosquito cells. During the analysis, Xiaoxia Ren, a postdoctoral fellow with Johns Hopkins Malaria Research Institute, noticed an "artifact," that appeared as a prominent band in the gel used to detect the bacteria...

The mother-daughter relationship can be difficult to understand. Why are the two so different? Now a Northwestern University study shows how this happens. In yeast cells, that is.

A research team has discovered a new mechanism for cell fate determination -- how one cell, the daughter, becomes dramatically different from the mother, even though they have the same genetic material. The study shows why mothers and daughters differ in how they express their genes.

By studying yeast, whose entire genome is known, scientists can learn the basics of cell division and apply that knowledge to the human system. Many of the fundamental mechanisms for cell division in yeast are conserved, or very similar, in mammals; many of the proteins involved in human disease are related to proteins that are involved in yeast cell division.

The new knowledge about cell fate determination could lead to a better understanding of healthy human cells, what goes awry in cancer cells and how human stem cells and germ cells work.

"Cancer may reflect a partial and aberrant loss of differentiated character, in which cells that were formerly specified to perform a specific task 'forget' that, and become more like the rapidly dividing stem cells from which they came," said Eric L. Weiss, assistant professor of biochemistry, molecular biology and cell biology in Northwestern's Weinberg College of Arts and Sciences. Weiss led the research team, which included scientists from the Massachusetts Institute of Technology...

- Exploding Chromosomes Fuel Research About Evolution Of Genetic Storage

ScienceDaily (Aug. 24, 2008)

Human cells somehow squeeze two meters of double-stranded DNA into the space of a typical chromosome, a package 10,000 times smaller than the volume of genetic material it contains.

"It is like compacting your entire wardrobe into a shoebox," said Riccardo Levi-Setti, Professor Emeritus in Physics at the University of Chicago.

Now research into single-celled, aquatic algae called dinoflagellates is showing that these and related organisms may have evolved more than one way to achieve this feat of genetic packing. Even so, the evolution of chromosomes in dinoflagellates, humans and other mammals seem to share a common biochemical basis, according to a team Levi-Setti led. The team's findings appear online, in Science Direct's list of papers in press in the European Journal of Cell Biology.

Packing the whole length of DNA into tiny chromosomes is problematic because DNA carries a negative charge that, unless neutralized, prevents any attempt at folding and coiling due to electrostatic repulsion. The larger the quantity of DNA, the more negative charge must be neutralized along its length....

PHOTO This false-color image of the distribution of calcium in the chromosomes of a deer was obtained using secondary ion mass spectrometry with the University of Chicago's high-resolution scanning ion microprobe.The same technique applied to single-celled organisms called dinoflagellates are providing new insights into the evolution of chromosomes. (Credit: Courtesy of Riccardo Levi-Setti)

Yale University scientists today reported evidence suggesting that the tiny cilia found on brain cells of mammals, thought to be vestiges of a primeval past, actually play a critical role in relaying molecular signals that spur creation of neurons in an area of the brain involved in mood, learning and memory.

The cilia found on brain cells of mammals until recently had been viewed as a mysterious remnant of a distant evolutionary past, when the tiny hair-like structures were used by single-celled organisms to navigate a primordial world.

“Many neuroscientists are shocked to learn that cells in the brain have cilia. Thus it was even more exciting to show that cilia have a key function in regulating the birth of new neurons in the brain,” said Matthew Sarkisian, post doctoral fellow in the department of neurobiology and co-first author on the study.

In the past decade, scientists have discovered primary cilia may have important functions in many animals. For instance, in 2000, Yale University scientists discovered defects in these cilia could lead to rare type of kidney disease. Researchers have been finding new functions for primary cilia ever since...

With oil prices skyrocketing, the search is on for efficient and sustainable biofuels. Research published this month in Agronomy Journal examines one biofuel crop contender: corn stover.

Corn stover is made up of the leaves and stalks of corn plants that are left in the field after harvesting the edible corn grain. Corn stover could supply as much as 25% of the biofuel crop needed by 2030.

Scientists with the USDA-ARS Agroecosystem Unit located at the University of Nebraska examined the long-term sustainability of using corn stover as a biofuel crop.

When corn stover is not harvested as a biofuel crop, it can be left on the fields to restore vital nutrients to the soil. Full-scale harvesting of corn stover may deplete the soil.

Researchers measured the soil organic carbon levels and residue production over 14 years in fields planted continuously with corn, continuously with soybeans, and with a rotation of corn and soybeans. Organic carbon rates were found to stay steady or even increase in all three field types...

A new test for West Nile virus in horses that could be modified for use on humans and wildlife may help track the spread of the disease, according to an article in the September issue of the Journal of Medical Microbiology.West Nile virus infects a wide range of animals, including humans, horses, dogs, cats, bats, squirrels, rabbits and birds. It is widely distributed in Africa, the Middle East and Europe. It was first reported in North America in 1999, when there were human fatalities in New York City. Since its arrival in the USA it has spread rapidly across the continent. The virus sometimes causes swelling of the brain, or encephalitis, which can be fatal. It is transmitted by several species of mosquito. Because the mosquitoes feed on so many different creatures the virus spreads quickly in areas where it has been introduced.

"Thousands of cases of West Nile virus have been reported worldwide, but 80% of infected people don't show any symptoms," said Dr Louis A Magnarelli, Director of The Connecticut Agricultural Experiment Station in the USA. "It is important to have highly sensitive and specific tests to diagnose infections and also to help track the ecology and epidemiology of West Nile encephalitis."

The US researchers have found that a new test designed to detect antibodies produced by horses is highly effective at diagnosing West Nile virus infections. Compared to the standard test for West Nile virus, the new test is much faster and gives accurate results. It was also useful in confirming past infections...